1. Field of the Invention
This invention relates to a strap fastener for adjustably connecting a strap, belt or band to a variety of articles.
2. Description of the Prior Art
Various adjustable strap fasteners or buckles have been proposed which may be manipulated to adjust the effective length of a strap on for example a bag or a safety seat belt on a motor car.
Advanced such fasteners are made of a plastic material formed into an integrally molded structure which generally comprises a pair of opposing side flanges, a grip end portion at one end of the side flanges, an anchor end portion at the opposite end of the side flanges and a plurality of parallel cross bars disposed in between the grip and anchor end portions and extending transversely across between the side flanges. In use, one end portion of a strap or the like is looped about one of the cross bars, passed under the anchor end of the fastener and secured in place as by rivetting. The other end portion of the strap which is adapted for length adjustment is looped about another cross bar, passed under the grip end of the fastener and gripped therebetween against displacement. For ease of insertion or passage of the strap between the cross bar and the grip end portion, the gap therebetween is desirably the larger the better. Conversely, however, the larger the gap, the tendency will be greater for the strap to get loose under tension. Vice versa, this tendency is less the smaller the gap, but the insertion of the strap becomes more difficult.
A proposal has been made to thicken the fastener, or to incline the gap defining surfaces instead of enlarging the insertion gap, as disclosed in Japanese Patent Kokai (laid-open) Publication No. 54-144244. Such attempts are however not satisfactory in that the resulting fastener is costly and becomes unsightly.